Automatic popcorn popper with thermal controller

ABSTRACT

Apparatus and methods for popping popcorn comprise a heated kettle which is controlled and monitored according to the temperature of the kettle. The kettle is initially heated to a start cook temperature and a buzzer and light alert an operator to add uncooked popcorn and oil to the kettle which lowers the temperature of the kettle below a predetermined start temperature and initiates a cooking cycle. An oil pump system is enabled at the initiation of the cooking cycle for adding oil to the kettle. As the popcorn and oil cook, the kettle temperature increases and passes through a predetermined dump temperature and the kettle automatically tilts and dumps the cooked popcorn. After the dump, the kettle temperature increases to the start cook temperature again and the buzzer and light are activated to alert the operator to add another batch of ingredients for consecutive batches of popcorn.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation-in-part of application Ser.No. 08/345,303 entitled, “Automated Corn Popper” and filed Nov. 28,1994; which application is incorporated herein by reference in itsentirety.

FIELD OF THE INVENTION

[0002] This invention relates generally to popcorn poppers and morespecifically to an automatic popcorn popper which produces popcorn inconsecutive batches while reducing the amount of attention required froman operator. This invention also relates to an improved method forpopping popcorn.

BACKGROUND OF THE INVENTION

[0003] Popcorn is mass-produced for sale at movies and other events incommercial popcorn poppers which include an enclosed, transparentcabinet containing a tiltable kettle suspended above a catch area orplatform. The kettle is heated and uncooked popcorn kernels are placedtherein to be cooked and popped. Once the kernels are popped, the kettleis manually tilted and the popcorn spills onto the platform to bescooped up, packaged and sold to customers.

[0004] Conventionally, commercial popcorn poppers have been manuallyoperated and have required an operator's constant attention for cookingthe kernels and subsequently dumping the popped popcorn. For example, anoperator would load the kettle with popping oil and unpopped cornkernels and then listen and watch for the unpopped corn to pop. When theoperator decided, somewhat arbitrarily, that the corn was sufficientlypopped, they would then dump the kettle and spill the popcorn onto theserving platform. Additional oil and corn would then be added for thenext batch. While such conventional popcorn poppers are generallyeffective in mass-producing popcorn; the constant attention they requireprevents the operator from other important tasks, such as selling thepopcorn and other concession products, taking money and generallyservicing customers.

[0005] As may be appreciated, the multiple duties entrustedconcessionaire operators are not conducive to having them constantlymonitor a popcorn popper. If attention is diverted for an extendedlength of time, the popcorn is susceptible to being burned orovercooked. In addition to the waste of burned popcorn, the aroma of theburned popcorn is not attractive to customers and may actuallydiscourage purchases. Furthermore, if the operator inadvertently dumpsthe burned corn onto the platform, it will contaminate the usablepopcorn which has already been produced and may render the entire batchinedible and thus unusable. Still further, the results and mess fromburned popcorn is not easy to clean. The kettle is hot and must beallowed to cool before the burned popcorn is removed and the kettleplaced back in service.

[0006] Additionally, the arbitrary nature of the dumping process withconventional poppers makes them subject to messes associated withpremature dumping. For example, if the operator mistakenly believes thatthe corn has been completely popped and the oil used when indeeduncooked corn and oil remains in the kettle, tilting the kettle willspill oil onto the serving platform and possibly onto the counter. Suchspills ruin and waste popcorn and create a mess which must be cleaned,adding to the already numerous tasks of a concessionaire.

[0007] Still further, too much oil may be added for a particular cookingcycle, and even if the cooking cycle is completed, excess oil might beleft, again resulting in a mess upon dumping of the batch. For example,one operator may load the uncooked corn and oil for a batch, and anotheroperator may subsequently and inadvertently load more oil, believing ithad not been added. The excess oil does not burn off or cook and remainsin the kettle. Not only is a mess created upon dumping, but the excessoil may also foul the batch of popcorn.

[0008] Another drawback of conventional popcorn poppers is the inherentdelays which will occur between cooked batches of popcorn. When thepopcorn has been cooked and dumped, the operator may begin serving it tocustomers without replenishing the supply of corn and oil and startingthe next batch. Therefore, the next batch of popcorn will not beproduced until the operator consciously sets aside time from his otheractivities to do so. Such delays interrupt production rates andintroduce inefficiencies into the operation which reduce popcorn sales.

[0009] It is also desirable to pop popcorn consistently so that itproduces consistent taste from batch to batch. The vagaries of priorsystems leave much to chance in this regard so that batches of corn areundercooked, burned or the like and at the least are inconsistent intaste.

[0010] Still another drawback to conventional popping mechanisms is thatthey sometimes provide inconsistent or improper heating of the popcornso that proper expansion of the kernels upon popping is not achieved.Particularly, when the heat is too high, the steam from the kernel isprematurely forced out and the popped kernel is small. If thetemperature is too low, the kernels do not experience proper hullexpansion and brittleness at popping and the popped kernels are small.As may be appreciated, small popcorn kernels reduce the yield of poppedpopcorn per unit of uncooked kernels, thus reducing the efficiently ofthe popping apparatus and raising the cost of the operation.

[0011] As a result, it is one objective of the present invention toprovide improved apparatus and/or methods to pop popcorn continuously inconsecutive batches with minimal attention by an operator.

[0012] It is another objective to ensure that the popcorn isconsistently and properly cooked in each batch.

[0013] It is a further objective of the present invention to reduce theburning of popcorn sometimes associated with conventional machines andoperator inattention.

[0014] It is also an objective of the invention to always provide theproper amount of cooking oil and thus reduce the messes associated withsuch burned popcorn or spilled, uncooked oil and thereby allow anoperator to focus upon customers and popcorn sales.

[0015] It is a still further objective of the invention to reduce thedelays between fresh batches of popcorn attributable to lack ofattention by the operator.

[0016] It is a still further objective of the invention to increase theproduction rate of consecutive batches of fresh popcorn to therebyincrease the sales from and the profitability of a commercial popcornpopper.

[0017] Still further, it is an objective to provide the proper andconsistent temperature to the kernels as they cook to ensure properpopping conditions and to maximize the popcorn yield per unit ofkernels.

SUMMARY OF THE INVENTION

[0018] Addressing these objectives, the present invention comprises apopcorn popper which may be left unattended to automatically cook anddump popcorn once it has been loaded with the proper ingredients, suchas uncooked popcorn. The proper, premeasured amount of oil pump is thenadded by the oil pump system upon the initiation of a cooking cycle sothat the operator does not have to worry about measuring oil or excessoil in the kettle. The popcorn popper of the invention is responsive tokettle temperature conditions to automatically cook popcorn kernels,subsequently dump the finished popcorn, and then alert the operator toload more ingredients such as oil and uncooked kernels, and start thenext batch. In that way, all of the batches of fresh popcorn areproperly cooked at regular periods with the proper amount of oil andheat, and the operator is left to attend to other tasks.

[0019] According to the invention, popcorn is consistently cooked byintroducing an amount of popcorn and oil to a cooking system, comprisinga heated kettle, for a duration sufficient to heat the corn and oil apredetermined amount, and then automatically dumping popped popcornafter a sufficient amount of heat energy has been absorbed by the cornand the oil to pop the corn. The application of heat energy to the cornand oil is not monitored and controlled by time, but rather by the heatconditions of the cooking system for each batch. In this regard, akettle is heated to a start temperature and cycled about thattemperature through a small temperature range. When unpopped corn andoil are introduced, a thermocouple on the kettle senses a temperaturedrop (cycle point) and a cooking or popping cycle begins. The corn andoil absorb the heat energy and are heated in the kettle until the kettletemperature climbs back to a predetermined temperature (dump point)indicating sufficient heat energy has been applied to the corn and oilto pop the corn. At that point, the kettle is automatically dumped.

[0020] Since the controller is temperature, rather then time responsive,the operator is assured a consistent amount of heat is always applied tothe corn and oil for consistent popping. If the kettle dump wascontrolled by time alone, and the environment changed, such as a cabinetdoor being open, the cooking cycle might time out before sufficient heatenergy was applied to consistently cook that batch of corn. Moreover,since the start temperature is held within a narrow predetermined range,the oil and corn will not be prematurely burned and the temperaturegradients applied thereto will be more consistent. Also, such a methodaccommodates at least some variations in the amount of corn and oilintroduced to the kettle. If too little, the temperature drop will notbe as great and the rise to the predetermined dump temperatures takes ashorter time, thus sufficient but less heat is introduced so this batchis consistently popped. In a corresponding manner, larger amounts ofcorn and oil will slow the climb of temperature to the dump pointinsuring that sufficient heat is imparted to pop the corn consistentlywith other batches.

[0021] To further ensure proper cooking by the invention, a premeasuredamount of oil is introduced to the kettle at the beginning of a cookingcycle. The controller is coupled to an oil pump system which is operablyin fluid communication with the kettle. Upon the kettle reaching theproper start temperature or cooking temperature, the oil pump system andan oil pump switch are enabled. The operator then actuates the oil pumpswitch to activate the pump system and deliver a proper, premeasuredamount of oil to the kettle. The oil pump system and switch are disabledby the controller if the kettle heat is not ON (no cooking cycle) or thekettle is tilted from an upright position, such as to be cleaned.Furthermore, in accordance with the principles of the present invention,the oil pump system will only deliver one load of oil per cooking cycleto prevent an oil overload or spilling of oil when the cooked batch ofpopcorn is dumped. Therefore, the oil pump switch may be actuatednumerous times and only one load of oil will be delivered per cookingcycle.

[0022] In an alternative embodiment of the invention, the controller isoperable to activate the oil pump system automatically upon theinitiation of a cooking cycle. To that end, the controller provides anoutput signal to the oil pump system to pump a premeasured amount of oilto the kettle at a predetermined time in the cooking cycle. For example,the oil might be added when the kettle has risen to a start temperatureor might be added after the popcorn has been added. If the oil pumpsystem has a mechanically adjusted timer mechanism for pumping apremeasured amount, an output signal is provided by the controller toactivate the pump and pump oil into the kettle. If the oil pump systemincludes a programmable timer mechanism, the controller is operable toprovide additional timer outputs to adjust the amount of time that thepump will deliver oil when activated. In either case, a premeasured andproper amount of oil is delivered to the kettle each cooking cycle. Thecontroller will not activate the pump system until the kettle is hot andready to cook and is upright.

[0023] More specifically, the popper apparatus includes a kettle whichis coupled to a dumping motor and a heater which are controlled by acontroller which monitors the kettle temperature. The controllerincludes a temperature sensor, such as a thermocouple, which is operablyconnected to the kettle proximate the heaters. By monitoring thetemperature of the kettle, the controller is operable to dump the kettleat the proper time and to alert the operator when another batch ofuncooked corn kernels should be added to the kettle. Since the kettletemperature is constantly monitored, and the dump cycle is automaticallycontrolled, the burning of popcorn is prevented. Furthermore, anoperator does not have to constantly monitor the procedure to preventsuch burning and can thus turn his attention to other tasks. The popperbegins a cooking or popping cycle when fresh ingredients are added, andby alerting the operator at the end of each popping cycle, the poppereffectively reduces the delay between batches to increase itsproductivity.

[0024] In a preferred embodiment of the invention, a programmable logiccontroller (PLC) is coupled to a temperature controller which, in turn,is coupled to a kettle thermocouple and to kettle heaters. When thepopper is turned ON and the kettle heat is turned ON, the kettle isheated to an equilibrium start or cooking temperature of, for example,approximately 525° F. The thermocouple and temperature controllerpreferably maintain the desired 525° F. kettle cooking temperature in asmall cycled range of +/−10° F. When the kettle has reached theequilibrium start temperature, the PLC activates indicators whichprovide visual and audible indications that the kettle is ready to makepopcorn. The oil pump system and pump switch are enabled and theoperator actuates the oil pump switch to load the oil which is pumped inby the oil pump, and also loads the uncooked popcorn kernels.

[0025] Alternatively, the oil might be loaded by hand by the operator.In still another alternative embodiment of the invention, as discussedabove, the PLC provides outputs directly to the oil pump system toautomatically pump oil to the kettle at the initiation of a cookingcycle. The PLC is operably coupled to the oil pump system to activatethe pump for a predetermined amount of time to ensure a premeasuredamount of oil. A timer determines how long the pump runs once activatedto ensure the proper amount of oil. The invention may incorporate an oilpump system having a mechanically adjusted timer, such as a dial timer,or may incorporate a system having a separate programmable timer. In thelatter case, the PLC is operable to provide separate output signals tothe programmable timer to set the pump time in addition to any outputsignals to the pump for delivering oil for the amount of time set by thetimer.

[0026] The temperature controller senses the rapid drop in kettletemperature associated with the absorption of heat from the kettle bythe corn and oil. When the temperature drop exceeds a set amount, forexample, 50° F. below the equilibrium start temperature, the PLCinitiates a cooking cycle. The point of initiation of the cooking cycleis designated the cycle temperature or cycle point.

[0027] As the cooking cycle progresses, the PLC senses through thetemperature controller, that the kettle has dropped to a minimumtemperature below the cycle temperature. The minimum temperature willdepend upon the heat load added to the kettle. As the popcorn pops, thetemperature of the kettle begins to rise above the minimum temperature.When the kettle temperature reaches a predetermined dump temperature ordump point and the PLC that the minimum temperature was previouslyreached and was preceded by the cycle temperature, the popper indicatesthat the end of the cooking cycle has occurred. Preferably, thepredetermined kettle dump temperature associated with the dump point fordetermining the end of a cooking cycle is equal to the cycle temperatureassociated with the start of the cooking cycle, i.e., approximately 50°F. below the equilibrium start temperature, for example. Upon sensingthe end of the cooking cycle at the dump point, the PLC initiates a dumpcycle and controllably energizes the dump motors to tilt the kettle anddump the finished popcorn onto the surface platform. The popcorn isimmediately and automatically dumped at the end of a proper cookingcycle, therefore preventing the popcorn from burning. Furthermore,because of the unique temperature-driven control of the popper, thepopcorn is consistently and properly cooked and may be served at thepeak of freshness. The greater the amount of corn and oil added, thelonger the cooking cycle. Conversely, the less the amount of corn andoil, the shorter the cooking cycle.

[0028] Preferably, the motors are controlled to dump the kettle twice toensure complete dumping. After the first dump, the kettle is onlypartially returned to a cooking or popping position. It is then dumpedagain before fully returning to a popping position.

[0029] When the temperature controller indicates that the kettletemperature is below the cooking cycle point and the machine is in acooking cycle, the PLC disables the dump motors and thus preventsinadvertent dumping of the kettle contents.

[0030] When the popcorn has been dumped at the end of a cooking cycle,the kettle will heat back up to the start cook point again, and audibleand visual indications are again initiated to remind a busy operator toreload the kettle with fresh ingredients. This prevents delays inbetween consecutive batches of popcorn and thus increases the efficiencyof the operator and the popcorn popper, increasing production rates andprofitability.

[0031] The present invention provides the proper application of heatenergy consistently to batches of corn kernels. In that way, the kernelsare heated to a sufficient temperature to provide proper hullbrittleness and expansion when the kernels pop but the heat is not sohigh so as to force out the steam in the kernel prematurely. Therefore,the invention achieves the desired corn temperature and peak steampressure for proper expansion. Expansion rates of approximately 1:50have been achieved with the invention which is a significant improvementover some conventional devices which achieve expansion rates of 1:44 orlower.

[0032] Therefore, the present invention automates the cooking anddumping of popcorn and eliminates the need for constant operatorattention to the process. Production of consistently popped corn isincreased as is the profitability of the operation while incidents ofburned corn and inadvertently spilled oil or uncooked corn areeliminated. Furthermore, the temperature control of the kettle operationand the cooking cycle provides properly and consistently cooked batchesof popcorn.

[0033] The above and other objectives and advantages of the presentinvention shall be made apparent from the accompanying drawings and thedescription thereof.

BRIEF DESCRIPTION OF THE DRAWING

[0034] The accompanying drawings, which are incorporated in andconstitute a part of this specification, illustrate embodiments of theinvention and, together with a general description of the inventiongiven above, and the detailed description of the embodiments givenbelow, serve to explain the principles of the invention.

[0035]FIG. 1 is a perspective view of a popcorn popper apparatus inaccordance with the principles of the invention;

[0036]FIG. 1A is a perspective view of the top of the popcorn popper ofFIG. 1;

[0037]FIG. 1B is perspective view of the popcorn popper of FIG. 1illustrating the oil pump system.

[0038]FIG. 2 is a cross-sectional view of a popcorn popping kettle asseen on line 2-2 of FIG. 1;

[0039]FIG. 3 is a cross-section taken along lines 3-3 of FIG. 2;

[0040]FIG. 4 is a perspective-view of the kettle of the popcorn popperof FIG. 1;

[0041]FIG. 5 is a perspective view of the kettle of FIG. 4 removed fromits housing for cleaning;

[0042]FIG. 6 is a diagrammatic view of the electrical components of thepopcorn popper of FIG. 1;

[0043]FIG. 7 is an operation flowchart of the popcorn popper apparatusof the invention; and,

[0044]FIG. 8 is a temperature graph versus time of the kettle during apopcorn cooking cycle.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

[0045] Turning now to the drawings, there is shown in FIG. 1 anautomated corn popper 10 according to the invention. It will beappreciated that the popper is operable to cook or to pop popcorn and isparticularly useful for cooking consecutive batches of popcorn for salefor use by concessionaires at movie theaters, sport events, fairs andthe like.

[0046] The corn popper 10 includes a cabinet having transparent wailsincluding two sidewalls 11, 12, a rear wall 13, front wall 14, and aservice platform 17 for catching popcorn. Front wall 14 includes twodoors 15, 16, which can be opened to gain access, both to the poppedcorn on the platform 17 of the cabinet and to the kettle 18. Sidewalls11, 12 and rear wall 13, as well as the front wail 14 including doors15, 16, are all made preferably of transparent glass or plastic materialso that the interior of the cabinet can be viewed from the exterior. Thecabinet may also include various operating switches and light indicatorson an operating panel 25 for turning ON kettle heat, the dump motor, awarmer (not shown) under platform 17 and lights inside the cabinet aswell as turning ON the heaters and pumps of an oil pump system (see inFIG. 1B) for providing cooking oil for the operation. The lights mayindicate that one or more of these systems are ON. Various of thesesystems will now be described in greater detail in accordance with theprinciples of the present invention.

[0047] The cabinet of popper 10 also preferably includes an oil pumpsystem 36 which would rest below the platform in the cabinet (see FIG.1B). The oil pump system 36 provides oil to the kettle during a cookingcycle and might be one of various different systems. For example, GoldMedal Products Co. of Cincinnati, Ohio, which is the owner/assignee ofthe present patent application, markets the Model 2114 Accumeter BucketPump for pumping popcorn oil. Another system, Model 2257 Rack OilDelivery System, is also available from Gold Medal Products and isdiscussed in U.S. patent application Ser. No. 08/541,469 entitled “OilSupply for Popcorn Poppers”, which application is incorporated herein byreference in its entirety. While those oil systems manufactured by GoldMedal Products Co. are preferable, the present invention might beutilized with other systems as well.

[0048] The popping kettle 18 is of any suitable variety having a heater(not shown in FIG. 1) interconnected by a control line 19 to a powerplug 20 mounted inside on the top 21 of the cabinet, It will beappreciated that the kettle 18 is tiltable about a tilt axis 22 (FIG. 2)and is provided with covers 23 and 24 which are pivoted on the kettle18. When the corn is popped, it pushes these covers open and falls outthe sides of the kettle onto platform 17. Moreover, it will beappreciated that the cover 23 is located over a so-called “dump section”or side of the kettle 18. When the kettle is tilted, this cover pivotsopen to facilitate dumping of popcorn onto platform 17.

[0049] Positioned between covers 23, 24 is an oil funnel 29 which has aflared funnel mouth 30. When the kettle 18 is upright as shown in FIG.1, the funnel 29 aligns with an oil outlet 37 which is coupled via adelivery tube 39 to oil pump system 36. Oil is pumped up by system 36 todrain into funnel tube 29 and kettle 18 for use during a cooking cycleas discussed in greater detail hereinbelow.

[0050] The kettle 18 includes an internal agitator, stir blade or rotor38 (FIG. 3) driven by a rotor drive shaft 26 having an upper pilot end27 and a driven gear 28 thereon. Referring to FIG. 4, when the kettle isin a cooking position as shown in FIG. 1, the upper pilot end 27 of therotor drive shaft 26 is located in a socket 31 defined in a rotor drivehousing 32 adjacent a drive shaft 33 and a drive gear 34. The drive gear34 intermeshes with the driven gear 28 on the upper pilot end 27 of therotor drive shaft 26 to drive the rotor within the kettle to promotepopping. Directly above socket 31 in drive housing 32 is a positionsensor 35 which determines that shaft 26 is seated in socket 31 andkettle 18 is in a cooking position. The sensor 35 promotes more accuratepositioning of the kettle after it is tilted as discussed in greaterdetail below. The stir blade and shaft 26 are rotated by stir motor 68which is activated by an appropriate operating switch on the panel 25 orby the controller of the invention as discussed below.

[0051] Referring again to FIG. 3, the blade 38 of the invention isweighted to prevent popcorn from being trapped against the blade duringa dump cycle. As discussed further hereinbelow, the kettle 18 is tiltedor dumped during a cycle to dump out the cooked popcorn. To preventhindrance of the popcorn by blade 38, the blade is weighted on one sidewith an appropriate weight element 47 which causes the blade to rotateto a downward or generally vertical position during a kettle dump cycle.The blade 38 is then out of the way of the dumped popcorn so thatpopcorn falls freely from the kettle.

[0052] The kettle is mounted in the cabinet of the popper 10 by way of adrive housing 40 and a spring-like hanger bracket 41. The spring-likehanger bracket 41 includes an L-shaped bracket having a foot 42 forinterconnection to the top 21 of the cabinet. The depending flat springleg 43 is provided with an aperture or slot 44, as will be furtherdescribed.

[0053] On the other side of the kettle, the drive housing 40 houses thedrive shaft 48, which is provided with a worm gear 49 on the bottom endthereof. A drive stub shaft 50 is provided with a gear 51 forintermeshing with the worm gear 49. The opposite end of the drive stubshaft 50 is provided with a drive stub 52 disposed in a socket 53 of thedrive housing 40. The upper end of the drive housing 40 is provided witha mounting foot 54 for securing the drive housing 40 to the top 21 ofthe cabinet of the popper 10. In addition, it will be appreciated thatthe drive shaft 48 can be a one-piece drive shaft or it can be coupledthrough a coupling 55 to the depending drive shaft 56 of a dump motor 58(FIGS. 1 and 1A). Drive shaft 48 is journaled in a blind bore 45 locatedin an externally threaded bushing 46 in the bottom of housing 40 (FIG.3). This prevents lubricants from leaking into the popped pop corn.

[0054] The kettle 18 is provided with a drive boss 60 and a hanger boss61. The drive boss 60 is provided with a slot 62 for receiving the drivestub 52, supported by the drive housing 40. The hanger boss 61 extendsfrom the other side of the kettle with respect to the drive boss 60 andis provided with a groove 63 for receiving the depending leg 43 of thehanger bracket 41. In this regard, the groove 63 fits within a slot oraperture 44 of the hanger bracket 41 so that the kettle can be rotatedabout the pivot axis 22. At the other drive side of the kettle, thedrive boss 60 resides in the socket 53, defined by the drive housing 40,so that the drive boss 60 can rotate in that socket. It will beappreciated that the socket has an opening 64 for accommodating radialmovement of the drive boss 60 with respect to the socket and to thedrive stub 52 when the drive stub 52 and the recess 62 in the drive boss60 are aligned with the opening 64 to permit the drive boss to be movedoutwardly of the socket.

[0055] Alternatively, the kettle could be supported in a cantileveredfashion only by the drive boss or other supporting apparatus as will beappreciated.

[0056] Turning now momentarily to FIG. 1A, there is shown a perspectiveview of the top of the popper 10 showing various components of thepopper mounted outside the cabinet on the top 21 thereof including partsof the kettle operating system. The kettle operating system as it istermed herein includes the kettle heaters (not shown) and the kettledump motor 58 as well as the control components which operate the popperin accordance with the principles of the invention.

[0057] As shown in FIG. 1A, the dump motor 58 is mounted on the top 21,such that drive shaft 56 extends downwardly through the top 21 and intothe drive housing 40 (FIG. 3). A rotor drive motor or stir motor 68 isalso positioned on the top 21 so that its drive shaft 33 extendsdownwardly through the top 21 and through the housing 32 forinterconnection with the drive gear 34. A buzzer 70 is positionedpreferably on the top 21 as shown, as well as a cabinet light 75, aventilator 76 and various support circuitry for the components,including a Programmable Logic Controller (PLC) 77, a temperaturecontroller 82, and a solid state relay 86 to the kettle heaters.

[0058] The control components for the control system of the inventioncomprise a Programmable Logic Controller, or PLC, such as a PLC made byOmron Electronics, Inc., One East Commerce Drive, Schaumburg, Ill.60173, under the Model No. C20R. PLC 77 is connected to dump motor 58through an UP relay 78 and a DOWN relay 79. The PLC is also connected tothe audible buzzer 70 and to light 71 for audibly and visually notifyingan operator when the kettle 18 is ready to receive another batch ofpopcorn, oil, salt and other ingredients. The visual indicator light 71,which may be positioned on control panel 25, flashes to visually alertan operator that the kettle is ready for another batch of ingredientssimultaneous with the buzzing of buzzer 70. The visual indicator light71 will provide a visual indication to an operator and is particularlyhelpful in the case of multiple machines in an area where it may bedifficult to determine which one is buzzing. The PLC 77 provides outputsignals to the dump motor relays 78 and 79 to tilt the kettle and dumpthe popcorn cooked therein at the cessation of a cooking cycle. Outputsignals from the PLC 77 to the buzzer 70 and light 71 produce an audiblesignal and a visual signal which ensure consecutive batches of freshpopcorn without delays between batches as are normally associated withconventional popcorn machines.

[0059] The present invention is operable to monitor the temperature ofthe kettle to automatically alert the operator to load ingredients toautomatically begin a cooking cycle when ingredients are loaded, and toend the cooking cycle and automatically initiate a dump cycle to emptythe popcorn and again alert the operator to load more ingredients forthe next batch. The invention monitors the kettle temperature anddetermines at certain temperature checkpoints which operations are to beautomatically executed. Therefore, the popper of the invention may beloaded with corn and/or oil and then ignored until the next ingredientsload to free the operator to handle other tasks. To that end, thecontrol system of the invention further comprises a temperaturecontroller 82 to control the heating of kettle 18 and to provide inputsignals to the PLC 77 for initiating a popcorn cooking cycle andsubsequently for controlling dump motor 58 to dump finished popcorn fromthe kettle after a cooking cycle is complete. The temperature controller82 has an output line 84 which is operably coupled to a solid staterelay 86 connected to kettle heater 88. To provide a temperature inputto the PLC, a thermocouple 90 is operatively connected to kettle 18close to kettle heater 88 to monitor the temperature of the kettle. Anoutput signal on line 92 from the thermocouple is input into thetemperature controller 82. Through thermocouple 90 and line 92, thetemperature controller 82 monitors the temperature of kettle 18 andturns power to the heater 88 ON and OFF through solid state relay 86 tomaintain the temperature at a predetermined start temperature orequilibrium temperature. Preferably, the start temperature isapproximately 500° F. to 525° F., although it will be appreciated by oneof ordinary skill in the art that such a temperature might be varied upor down for a particular size kettle or other variable cookingconditions.

[0060] The temperature controller 82 communicates on line 94 directlywith the PLC 77. Line 94 is a low temperature alarm line which isutilized to set the beginning of the cooking cycle and to initiate akettle dump at the end of the cooking cycle. As described furtherhereinbelow, temperature controller 82 sends an input signal on line 94to the PLC 77 when thermocouple 90 indicates that the kettle temperaturehas dropped below a predetermined temperature or low alarm temperature,such as when uncooked popcorn kernels and oil are poured into the kettle18, and through thermal loading, cause a rapid decrease in the kettletemperature. The falling temperature passing through the low alarmtemperature point 149 indicates that a cooking cycle has been started(See FIG. 8). As may be appreciated, as the popcorn in kettle 18 cooks,the thermal load is reduced and the temperature of kettle 18 begins torise again. The kettle temperature will again pass through the low alarm150 temperature point, except this time as a rising temperature ratherthan a falling temperature, the rising temperature passing through thealarm point indicates the end of the cooking cycle (See FIG. 8). At sucha time, a signal is sent on line 94 to the PLC 77 to initiate a kettledump procedure to dump the cooked popcorn onto service platform 17 asdiscussed below. While the low alarm temperature may be variablyadjusted in temperature controller 82, it is preferably set to beapproximately 50° F. to 75° F. below the start temperature referencedabove, e.g., it may be set to be approximately around 425°-500° F.,depending upon the preferred start temperature. The temperature pointindicating the temperature 149 as it first falls through the low alarmtemperature when uncooked popcorn is added to the kettle is designatedthe cycle temperature or cycle point as it indicates to the PLC thebeginning of an official cooking cycle. A cooking cycle is not begununtil the kettle drops below the cycle temperature 149 to prevent falsecycles which might occur as the empty kettle fluctuates around the starttemperature (see FIG. 8). That is, the substantial drop from the starttemperature will indicate that corn and oil have been added to thekettle. The subsequent point 150 wherein the temperature increases backup to the low alarm temperature after the popcorn is cooked and poppedis considered the dump point or dump temperature because the PLCinitiates a kettle tilt to dump the popcorn at that temperature.Preferably, the cycle temperature 149 and 150 and dump temperature areapproximately the same (see FIG. 8), e.g., approximately 475° F.However, it may be appreciated that the temperatures might also beoffset from each other. Both the cycle temperature and dump temperatureare below the start temperature point.

[0061] In order to ensure stable heating of kettle 18, the temperaturecontroller 82 will preferably cycle solid state relay 86 and heater 88ON and OFF numerous times as the kettle temperature closely approachesthe equilibrium start temperature. This reduces substantial conditionsbeyond levels 142 and 152 of the kettle temperature which might occurshould the heater be turned OFF only at the time that the kettle reachesthe start temperature due to thermal transients in the system. Asuitable temperature controller for use with the invention is the Model935 Proportional Integral Derivative or PID, programmable temperaturecontroller available from Watlow, 1241 Bundy Blvd., P.O. Box 5580,Winona, Minn. 55987-5580. The Model 935 temperature controller 82 iscapable of monitoring when the kettle temperature is getting close tothe equilibrium start temperature and operably slowing down the heatingprocess as that start temperature is approached. The Model 935temperature controller also has an alarm silence feature which preventskettle dumping when the kettle is heating up upon initial powerup. Forexample, as discussed above, temperature controller 82 monitors a risingtemperature which reaches the predetermined low alarm temperature inorder to indicate the end of a cooking cycle and to control the dumpmotor 58 to dump the kettle. As may be appreciated, a rising temperaturepassing through the low alarm temperature is a scenario which will occurupon initial powerup as the kettle heats from a cold state to anequilibrium start temperature. In order to prevent a kettle dump atinitial powerup, temperature controller 82 has a start override featureto ignore the first rising pass 151 through the predetermined low alarmtemperature (See FIG. 8).

[0062] As the temperature controller 82 monitors the kettle temperature,it controls the operation of the heater 88 through solid state relay 86.The present invention alerts an operator when the kettle is ready tocook, and to indicate to the PLC 77 when kettle temperature has reachedthe equilibrium start temperature, a slave relay 96 is coupled to theoutput of relay 86 and provides an input to the PLC 77 on line 93. Whenthe solid state relay 86 is closed to provide power to the heaters 88 toheat kettle 18, a 24V signal is delivered to PLC 77 through slave relay96. When the solid state relay 86 closes and turns power to heater 88OFF and remains OFF, indicating that the kettle has reached starttemperature, (e.g., 525° F.) the slave relay 96 stops the signal to thePLC 77 and the PLC, in response, provides an output to buzzer 70 andlight 71 to produce an audible and visual indication and alert theoperator that the kettle is ready to cook popcorn. With consecutivebatches of popcorn, buzzer 70 and light 71 will again be energized toprovide an audible and visual indication indicating that the popcorn hasbeen cooked and dumped and the kettle is ready for another batch ofpopcorn kernels. In that way, consecutive batches are made withoutdelay.

[0063] The PLC 77 is also coupled to the kettle heat switch 80 tomonitor when the kettle heat to popcorn popper 10 is turned ON and OFF.When power to the kettle heater 88 is turned OFF, the PLC 77 willinternally reset a status bit. Thus, the PLC is not fooled intoinitiating a kettle dump when the power is turned OFF and then ON again,and in that way, the PLC 77 further prevents inadvertent dumping. Forexample, when the power and the heat to the kettle are turned ON byturning on switch 80 to deliver power to relay 86, the PLC 77 monitorsthe kettle temperature through temperature controller 82. If the heat 80is then turned OFF, kettle temperature would drop, simulating thermalloading of the kettle with fresh popcorn and oil when indeed no popcornor oil is loaded. If the kettle heat is then again turned ON, the PLC 77may note the rising temperature passing through the low alarmtemperature point and thus may believe that a batch of popcorn has beencooked and that it is time to dump the kettle. By resetting the PLC 77status bit upon an interruption of power to the heater 88, such ascenario is avoided. A high limit switch 98 is coupled to the kettleheater 88 to cut off the power to the heater if the kettle temperatureexceeds a set upper limit, such as if the solid state relay 86 staysopen or the temperature controller malfunctions.

[0064] The stir motor 68 turns a blade (not shown) during the cooking ofthe popcorn. In one version of the invention, stir motor 68 is turned onby a switch at the operating panel 25 and stays on. Alternatively, powerto the stir motor is routed through PLC 77 and is controlled by PLC 77as noted by line 73. PLC 77 operates the stir motor 68 so that the bladestirs automatically only during a cooking cycle and stops when thecooling cycle is complete independent of operator attention.

[0065] The oil for cooking the popcorn may be delivered either by hand,by the operator actuating a switch on the operating panel 25 which iscoupled to pump system 36, or alternatively may be handled automaticallythrough PLC 77 to automatically deliver oil at the initiation of acooking cycle. Oil pump system 36 preferably includes a reservoir 101, acontrol housing 103, and a pump 104 to pump oil from the reservoir. Thepump system 36 will also usually include a heater (not shown) forheating congealed oil to a liquid state before pumping. The heater maybe operably coupled to the control panel so that the oil may be properlyheated for being pumped to kettle 18.

[0066] In one embodiment of the invention, the oil pump 104 is operablycoupled to an oil pump switch 106 which is located at the operatingpanel 25. When the kettle heat switch 80 is ON and the kettle heats tothe start temperature, oil will be needed for a cooking cycle inaccordance with the principles of the invention, oil pump switch 106will be effectively disabled until all conditions are proper for acooking cycle. Switch 106 is operably coupled to PLC 77 as indicated byline 111 and the PLC 77 is operably coupled to oil pump 104 as indicatedby line 113. PLC 77 disables switch 106 until the kettle heat switch 80is ON, as indicated by control line 115 between switch 80 and PLC 77,until kettle 18 is upright, as indicated by proximity switch 35 coupledto PLC 77, and until kettle 18 is properly heated as indicated by thethermocouple 90 and controller 82. This prevents oil from being pumpedto funnel 29 from reservoir 101 until the kettle is hot and in theproper position.

[0067] Upon enablement of the oil pump switch 106, the operator mayengage the switch to deliver a premeasured amount of oil from reservoir101. Generally, pump 104 will be controlled by a timer 129 (see FIG. 6)which may be adjusted by a mechanically adjusted dial 117. In that way,the pump 104 will pump oil to kettle 18 for a predetermined amount oftime to deliver the proper premeasured amount of oil. When the timer 129times out, the pump 104 stops. Upon delivery of the oil, PLC 77 willdisable switch 106 so that no more oil may be added until the nextcooking cycle. In that way excess, uncooked oil is generally not presentin the kettle, thus preventing any spills or messes. Pump 104 is coupledto line 39 for oil delivery.

[0068]FIG. 1B illustrates the oil pumping system which is the subject ofU.S. patent application Ser. No. 08/541,469 and greater detail about theoperation of the system is given therein. Pump system 36 is usuallyreferred to as a bag-in-box system and includes a container 118 on topof control housing 103 which holds a flexible bag of oil 121. An oiltube 123 connects bag 121 and reservoir 101. Alternatively, an oilbucket or pail system, such as the Model 2114 Accumeter Bucket Pump (notshown) may be used.

[0069] In an alternative embodiment of the invention, the PLC 77 isoperably coupled to pump 104 and timer 129 by control lines 131, so thatdelivery of oil is automatic. When the kettle 18 heats up, and is in theproper upright position as discussed hereinabove, the PLC 77 willautomatically actuate pump 104, instead of enabling switch 106 andrequiring the operator to actuate the switch 106. Therefore, oil isdelivered automatically at the beginning of a cooking cycle. Theoperator then only has to add popcorn kernels, as the cooking cyclebegins. Timer 129 will control how long pump 104 runs once it isactuated to deliver the proper amount of oil. Timer 129 may be aprogrammable timer which is set by the PLC 77 control lines 131 and maybe programmed for certain, preselected amounts of oil for a batch. Thatis, the PLC 77 controls the timer 129 as opposed to a mechanicalmechanism such as dial 117. Once the timer 129 times out, pump 104 stopsand will not be reactuated until the next cooking cycle. As with theprevious scenario, if the kettle heat switch 80 is OFF, no oil is addedto the kettle.

[0070] It will be understood that various combinations of oil loadingsteps might be utilized in accordance with the principles of theinvention. For example, the oil pump 104 may require switch actuationwhile the timer 129 is automatically programmed by PLC 77. In anotherversion, the pump 104 may be automatically actuated by PLC 77 whiletimer 129 is manually set by a dial 117 or other mechanical device. Theoil system 36 will generally include a preheater (not shown) forliquefying the oil prior to pumping. The preheater may be actuated atthe control panel 25 or directly at the control housing 103 of oilsystem 36.

[0071] As the popcorn and oil are cooked during the cooking cycle andthe kettle temperature begins to rise, it rises through the low alarmtemperature 150 point or dump point as discussed above. A kettletemperature rise through the low alarm point or dump point which waspreceded by a cycle point indicates the end of a cooking cycle and theinvention is then operable to initiate a dump cycle. At the initiationof the dump cycle, the PLC 77 actuates the DOWN relay 79 to direct thedump motor 58 to rotate the kettle downwardly and thus dump thecontents. The down relay is actuated for a predetermined period of timeand then the relay is deactuated. Assuming that the cooking position ofthe kettle as illustrated in FIG. 1 is 0°, the kettle is rotatedapproximately 180° for the first dump to dump the popcorn contentstherefrom. That is, the kettle is turned upside down. Subsequently, thePLC 77 actuates the UP relay 78 to energize dump motor 58 and move thekettle 18 toward the cooking position. However, the UP relay is onlyactuated to return the kettle partially to its cooking position and infact is preferably energized for a time period sufficient to move thekettle to an approximately 60° angle between the 0° cooking position andthe dump 180° position. This partial return is obvious to the operatorand prevents him from believing the kettle is in the cooking position.Therefore, the operator is not misled into prematurely loading popcornand oil into the kettle.

[0072] After the partial return toward the cooking position, the DOWNrelay 79 is again actuated to make the dump motor 58 rotate the kettledownwardly to 180° to again dump the popcorn contents. The two-stagedump cycle of the present invention provides proper and complete dumpingof all the contents from kettle 18 so that little or no popcorn remainsin the kettle to be burned during the next cooking cycle. After thesecond dump, the UP relay 78 is actuated to energize dump motor 58 toreturn the kettle to the upright cooking position. Thus, the kettle 18is rotated to a full dump position, partially returned, rotated to afull dump position again, and then fully returned to the cookingposition for another cooking cycle.

[0073] Referring again to FIG. 4, when kettle 18 is returned to thecooking position, the upper pilot end 27 of drive shaft 26 engagessocket 31, and in doing so will actuate the proximity switch 35.Proximity switch 35 is preferably a metal detecting proximity switchwhich indicates the presence of the shaft end 27. Upon sensing the shaftend 27, the proximity switch 35 provides an input to PLC 77 which thensimultaneously actuates both the UP and DOWN relays 78, 79 to lock thedump motor 58 and provide a secure stop when the kettle is returned tothe cooking cycle. Proximity switch 35 provides secure placement of thekettle in the cooking position and allows rapid return of the kettle tothat position without slowing the motor down as the kettle approaches.The present invention thereby prevents overshoot of the shaft end 27 andsocket 31 and also ensures that the gears 28 and 34 are properly seatedfor the next cooking cycle. The proximity switch also ensures that oilcan be added to the kettle 18 only when the kettle is upright.

[0074] Upon the return of the kettle 18 to the cooking position with thekettle heated back up to the start position, PLC 77 again actuatesbuzzer 70 to provide an audible indication to the operator that anotherbatch of ingredients should be added to the kettle. In that way,consecutive batches of popcorn are made with very little delay betweenthe batches. Thus, the productivity of the operator and the popper 10and the profitability of the entire operation, is increased. PLC 77operates to actuate buzzer 70 at ten second intervals until newingredients are loaded into the kettle 18. In that way, the operatorcannot ignore the popper 10 of the invention as it will continue toalert him until another batch of ingredients is loaded. If the buzzer isignored for ten minutes, it will begin to sound continuously.

[0075] Kettle 18 may also be removed and cleaned as described in theparent application entitled AUTOMATED CORN POPPER referenced above. Tothat end, the PLC 77 is operably coupled to a clean switch 99. When theclean switch is actuated, PLC 77 is operable to actuate the DOWN relay79 and dump motor 58 to tilt the kettle 18 to a position between thecooking position and the full dumping position. In this intermediateposition, the plane of the drive stub 52 is aligned with the opening 64and the socket 53, thereby permitting the drive bar 60 of the kettle tobe lifted out of the socket, cleaned, and then subsequently replaced forfurther popcorn cooking as illustrated in FIG. 5.

[0076] Further understanding of the present invention may be obtained bya discussion of the operation of the invention and particularly tooperation of PLC 77. An operational flowchart is illustrated in FIG. 6.

[0077] Prior to beginning a cooking cycle or in order to clean thekettle, the heat switch 80 should be OFF (block 95). The PLC 77 thenchecks to see if the kettle is cool (block 100). If the kettle is cool,the clean switch 99 is enabled by the PLC 77 (block 102). The cleanswitch may then be actuated to tilt the kettle 18 for cleaning. Thekettle is then cleaned and returned to the upright position (block 127).As will be recognized, the kettle does not always have to be cleaned,and an operator may proceed directly to a cooking cycle wherein theprocess begins at block 105.

[0078] To begin a popping operation, the operator turns on the varioussystems of the popper. For example, the operator would turn ON the heatswitch 80 to the kettle heater 88 to deliver power to kettle heater 88through the relay 86. If necessary, the kettle stir motor 68 would beturned ON at panel 25 or may automatically be controlled by the PLC 77.The oil pump system 36 and any components, such as an oil preheater,might also be turned ON as indicated by block 105. When the kettle heatswitch is ON, the PLC 77 monitors the kettle temperature throughtemperature controller 82 as indicated at block 107 in FIG. 7. As thePLC 77 monitors the temperature, it continuously checks to determine ifthe kettle temperature has risen to the low alarm temperature pointwhich may indicate either that the kettle is initially heating up or isreturning to its equilibrium start temperature after having cooked abatch of popcorn (see block 108). As indicated by line 109, the PLC 77will continue to monitor the kettle temperature until it has risen tothe low alarm temperature point. When it has reached the low alarmpoint, as indicated by line 110, the PLC 77 determines whether thesystem is initially being powered up and has not yet cooked the firstbatch of popcorn (see block 112). As discussed hereinabove, thetemperature controller has a start override feature which ignores thefirst rising temperature pass through the low alarm temperature whichindicates that the system is initially being powered up. By ignoring thefirst low alarm temperature point, the dump cycle is not initiated asindicated by block 114. Otherwise, when the rising temperature returnsto and passes through the low alarm temperature point, a dump cyclewould normally be initiated according to block 116 because a low alarmtemperature point preceded by another low alarm point (cycle point) willindicate the end of a cooking cycle and a dump point as described above.

[0079] As the PLC 77 and temperature controller monitor the kettletemperature, the PLC 77 checks to see if the kettle temperature hasrisen to the equilibrium start temperature which is preferablyapproximately 500° F. to 525° F., as indicated by block 118. If thekettle temperature has not reached the start temperature, the PLC 77continues to monitor the kettle until that temperature is reachedaccording to line 119. When the equilibrium start temperature has beenreached, the system indicates that the kettle is ready to be loaded withingredients to cook a batch of popcorn (line 120). At the starttemperature, a buzzer is sounded and a light flashed intermittently bythe PLC 77 to notify the operator that it is time to load popcorningredients and to start cooking according to block 122. The buzzer willsound intermittently at ten second intervals and will continue to soundfor ten minutes. If the operator ignores the buzzer for ten minutes, andno ingredients have been loaded, the buzzer will then soundcontinuously.

[0080] When the kettle is ready to cook, the PLC 77 checks to see if thekettle is upright (block 130). If not, the buzzer sounds continuously(block 132). If the kettle is upright, the oil pump switch 106 isenabled (block 134). At this point, the oil pump switch 106 may bemanually actuated to add a premeasured amount of oil to the kettle asdescribed above (block 135). After oil is added, the switch 106 will bedisabled as discussed above, so that no more oil may be added until thenext cooking cycle. Alternatively, the PLC 77 may automatically actuatethe oil pump system (block 137) as described above. At that point,popcorn is also added to initiate a cooking cycle. As may beappreciated, the automatic pumping of oil may be prevented until afterthe popcorn is loaded and a cooking cycle is initiated, as shown byblock 139. In that way, oil introduction is not premature, such as whenthe kettle heat switch is turned OFF while the buzzer is sounding andlight flashing to clean the kettle as discussed above. For example, oilmight not be automatically added until after the temperature of thekettle full of popcorn drops, indicating the initiation of a cookingcycle.

[0081] The PLC 77 then monitors the kettle temperature in order todetermine if the ingredients have been loaded. As discussed above, theuncooked ingredients such as corn and oil will act as a heat load andreduce the kettle temperature when they have been placed therein. Asnoted in block 124, the PLC 77 will continue to monitor the kettletemperature and if no ingredients have been loaded, i.e., kettletemperature has not dropped (line 125), the buzzer will continue tosound. If ingredients are loaded, the kettle temperature will dropsomewhat rapidly and will plunge below the low alarm temperature point(cycle point) 149 of the temperature controller (see FIG. 8). The buzzerthen stops buzzing and the light stops flashing. Popcorn is then cookedby the kettle (block 128).

[0082] As the buzzer 70 is sounding and light flashing 71, the operatorhas the alternative options of turning the machine off or loadingingredients. If the kettle heat switch 80 is turned OFF, the systemoperation essentially returns to block 95 to determine if it is safe toclean the kettle.

[0083] Returning now to block 128, as the popcorn is cooked, the kettlebegins to again heat up and the temperature controller 82 and the PLC 77continue monitoring the kettle temperature to determine if it hasrecovered or risen back up to the low alarm temperature point (dumppoint) 150 and proceeded through that point on its way back to anequilibrium start temperature (block 108). If the kettle temperature hasrisen to the dump point and it is not an initial power-up situation, asindicated by line 136, a dump cycle will be initiated as describedhereinabove (block 116). After the dump cycle is initiated, the systemeither returns to block 95 if the kettle heat switch is turned OFF toclean the kettle (line 138) or will continue to heat the kettle up toits equilibrium start temperature and will be ready for the next load ofingredients to cook the next batch of popcorn. As illustrated by block118 when the start temperature has again been reached, the buzzer willagain sound to notify the operator to load ingredients. Also, the oilpump switch will be enabled (block 134), after having been disabledafter oil was added for the previous batch.

[0084] In that way, the automated corn popper 10 of the presentinvention only has to be loaded with ingredients to continually producesuccessive batches of popcorn. Once the ingredients are loaded, theoperator can ignore the popper and the corn will be properly cooked anddumped to be ready for serving. An audible buzzer 70 and flashing light71 will constantly remind the operator when a new ingredients load isneed and a cooperative working relationship between the operator and thepopper is developed for producing consecutive batches of fresh popcornefficiently and safely while leaving the operator to more importanttasks such as selling the product. Furthermore, the temperature controlof the popper ensures that the right amount of heat is applied to eachbatch of popcorn for consistently cooked popcorn. Still further, theinvention controls an oil pump system to ensure that the proper amountof oil is added without excess.

[0085]FIG. 8 schematically illustrates the kettle temperature as afunction of time through initial power-up and a single cooking cycle.When the kettle heat is turned on, the kettle 18 heats up steadily untilit reaches an equilibrium start temperature as indicated by line 140.Preferably, an equilibrium start temperature will be around 500° F. to525° F., but may be adjusted accordingly, depending upon the popcornload and the size of the kettle and other heating factors as understoodby a person of ordinary skill in the art. The temperature controller 82of the invention is programmed with the equilibrium start temperatureand will automatically monitor the kettle temperature to determine whenit begins to approach the start point 144. The temperature controller 82will cycle the heater 88 accordingly to prevent a large amount ofovershoot as indicated by the decreasing slope of the curve as itapproaches line 140. When the start temperature is reached, the kettleheater 88 is cycled ON and OFF by relay 86 to maintain the kettle closeto the start temperature as indicated in the curve section designated byreference numeral 142. When ingredients, such as kernels and oil, areloaded, as indicated by the load point 144, the kettle temperature dropsoff somewhat rapidly as indicated on the curve by reference numeral 146.Depending upon the popcorn and oil load, the kettle temperature woulddrop to a low point 147, for example in FIG. 8, indicated around 325° F.As the kettle temperature drops, it will drop through a low alarm point149. This first low alarm point is designated the cycle point or cycletemperature, because the PLC 77 sees it as the beginning of a cookingcycle.

[0086] As the popcorn cooks, the kettle temperature again begins to riseas indicated by reference numeral 148 and will again pass through thelow alarm set point or dump point 150. At dump point 150, the end of thecooking cycle is indicated, and the PLC 77 responds by initiating a dumpcycle. Therefore, the cooking cycle is defined between the cycle point149 and the dump point 150, although some cooking of the popcorn willoccur before the cycle point 149 and after the dump point 150.

[0087] The dump cycle is a two-stage dump and empties the cooked popcornonto the serving platform to be sold. After the dumping cycle, thekettle temperature again rises to the equilibrium start temperature of525° F. and the heater will again be cycled ON and OFF to keep thekettle at that temperature indicated on the curve by reference numeral152. At the start temperature, the buzzer 70 will again sound and thelight 71 will flash to indicate to the operator that a batch of popcornhas just finished cooking and that a new load of ingredients should beadded to the kettle.

[0088] Line 154 illustrates the signal on line 94 from temperaturecontroller 82 to the PLC 77. When the low alarm temperature points arereached and exceeded (either cycle point or dump point) the output fromthe temperature control cycles oscillates from high to low at aninternal frequency. The square wave signal is used preferably to drivethe intermittent buzzer 70 and flashing light 71. When the temperatureof the kettle drops below the low alarm temperature point, the output oftemperature controller 82 stays high, which indicates that a cookingcycle is ongoing.

[0089] As described, the present invention continuously and properlycooks popcorn in consecutive batches with minimal attention by theoperator. Because the kettle is controlled by temperature and the dumpcycle is initiated automatically depending upon the kettle temperature,the popcorn is not burned and is not affected by operator inattention.Furthermore, the introduction of oil is controlled for a proper,premeasured amount only once during each cooking cycle. Messes andspills associated with the prior art devices are reduced, and areduction in the delays between fresh batches of popcorn will increasethe production rate of the popper and thereby increase sales andprofitability of the popper. Furthermore, the present invention insuresthat a consistent and proper amount of heat energy is always applied tothe corn for popping. The invention is not particularly susceptible toenvironment variations, and will ensure that the proper amount of heatenergy is applied to a batch of corn. Larger batches will get more heatenergy and small batches will get less heat energy to insure consistentpopping.

[0090] The present invention also provides the proper amount of heat tomaximize kernel expansion at popping. With the heat maintained at theproper level, the temperature of the corn and the steam pressure in thekernels will cooperate to provide consistent and high kernel expansion.With the present invention, popping expansion of rates of 1:50 have beenachieved which are a significant improvement over the 1:44 or lowerrates achieved by the prior art.

[0091] While the present invention has been illustrated by a descriptionof various embodiments and while these embodiments have been describedin considerable detail, it is not the intention of the applicants torestrict or in any way limit the scope of the appended claims to suchdetail. Additional advantages and modifications will readily appear tothose skilled in the art. The invention in its broader aspects istherefore not limited to the specific details, representative apparatusand method, and illustrative example shown and described. Accordingly,applicant intends to be bound only by the claims appended hereto.

What is claimed is:
 1. Apparatus for popping corn comprising: a kettle;a kettle operating system for heating and operating the kettle andpopping popcorn placed therein; a control system responsive to a kettletemperature condition and operably coupled to the kettle operatingsystem to control kettle operation in response to said kettletemperature condition.
 2. Apparatus as in claim 1 wherein the operatingsystem is operable to tilt the kettle, the control system being furtherresponsive to said kettle temperature condition to automatically tiltthe kettle and dump the popcorn when it is popped.
 3. Apparatus as inclaim 2 wherein the kettle operating system includes a dump motoroperably coupled to tilt the kettle and dump popped popcorn from thekettle, the control system operating the dump motor to automaticallydump the popcorn when it is popped.
 4. Apparatus as in claim 2 whereinthe control system causes the popcorn to dump when the kettletemperature exceeds a predetermined dump temperature.
 5. Apparatus as inclaim 4 wherein the kettle operating system further includes atemperature sensor coupled to the kettle for providing a kettletemperature signal indicative of the kettle temperature, the controlsystem operably coupled to receive the kettle temperature signal fordumping the popcorn when the kettle temperature exceeds saidpredetermined dump temperature.
 6. Apparatus as in claim 1 wherein thecontrol system is further responsive to provide a humanly perceptibleindication when the kettle temperature is heated to reach an equilibriumstart cook temperature to alert the operator that the kettle is ready tocook.
 7. Apparatus as in claim 6 wherein the kettle operating systemincludes an indicator and a heater operably coupled to heat the kettleto said start cook temperature, the control system providing saidindication through the indicator when the heater heats the kettle tosaid start cook temperature to alert the operator to load the kettlewith uncooked popcorn.
 8. Apparatus as in claim 7 wherein said indicatorincludes a speaker element for providing an audible indication to alertthe operator that the kettle is ready to cook.
 9. Apparatus as in claim7 wherein said indicator includes a flashing light for providing avisual indication to alert the operator that the kettle is ready tocook.
 10. Apparatus as in claim 1 wherein the kettle operating systemincludes a temperature sensor coupled to the kettle for providing akettle temperature signal indicative of the kettle temperature, thecontrol system operably coupled for receiving the kettle temperaturesignal and operable for initiating a popcorn cooking cycle when thekettle temperature decreases below a predetermined start temperature.11. Apparatus as in claim 1 wherein the kettle is tiltable and thekettle operating system includes a temperature sensor coupled to thekettle for providing a kettle temperature signal indicative of thekettle temperature and a dump motor operably coupled to tilt the kettle,the control system operable to receive the kettle temperature andinitiate a popcorn cooking cycle when uncooked popcorn is added to thekettle and the kettle temperature decreases below a predetermined dumptemperature and further operable to actuate the dump motor and dumpcooked popcorn from the kettle when the kettle temperature subsequentlyrises back up to and exceeds said predetermined dump temperature. 12.Apparatus as in claim 1 further comprising an oil delivery systemincluding a pump system and a reservoir of oil, the pump system operableto deliver oil from the reservoir to the kettle to pop popcorn therein,the control system further operable to disable the pump system inresponse to said kettle temperature condition.
 13. Apparatus as in claim2 further comprising a stir blade operably mounted to turn inside saidkettle, the stir blade being operable to rotating to a position when thekettle is tilted to allow generally unhindered dumping of the popcorn.14. Apparatus as in claim 13 wherein said stir blade is weighted on oneside thereof for rotating to said position when the kettle is tilted.15. Apparatus for popping popcorn comprising: a tiltable kettleincluding a heater to heat the kettle during a cooking cycle for poppinguncooked popcorn placed therein; a sensor operably coupled to sense thetemperature of the heated kettle and generate a temperature signalindicative of the kettle temperature; a dump motor operably coupled toselectively tilt the kettle from an upright position and dump thepopcorn; a control system operable to receive said sensed kettletemperature signal from the sensor and coupled to the dump motor toautomatically tilt the kettle from an upright position and dump thepopcorn when the kettle temperature exceeds a predetermined dumptemperature upon completion of the cooking cycle.
 16. Apparatus as inclaim 15 wherein the kettle temperature decreases to a minimumtemperature below said dump temperature when uncooked popcorn is placedin the kettle, the control system being responsive to the minimumtemperature signal and dumping the popcorn only when a dump temperaturesignal is preceded in time by the kettle minimum temperature signal. 17.Apparatus as in claim 15 wherein the control system is further operableto disable the dump motor and prevent the dumping of popcorn when thekettle temperature is below said dump temperature.
 18. Apparatus as inclaim 15 wherein said dump temperature is in the range of 425° F. to500° F.
 19. Apparatus as in claim 15 wherein the heater is operable tomaintain the kettle at an equilibrium start temperature above said dumptemperature when no popcorn is being cooked, the kettle temperaturedecreasing below a predetermined low temperature when uncooked popcornis added to the kettle, the control system responsive to a decrease inkettle temperature from said start temperature to a temperature belowsaid predetermined low temperature and initiating a cooking cyclethereupon.
 20. Apparatus as in claim 19 wherein said equilibrium starttemperature is in the range of 500° F. to 550° F.
 21. Apparatus as inclaim 19 wherein the kettle temperature subsequently increases as thepopcorn in the kettle is cooked during a cooking cycle and the controlsystem is responsive to such an increase, the apparatus furthercomprising an indicator coupled to the controller and operable toprovide a humanly perceptible indication when the kettle has risen backup to said equilibrium start temperature after the popcorn has beencooked and dumped such that an operator is alerted to add another batchof uncooked popcorn to the kettle and initiate another cooking cycle.22. Apparatus as in claim 15 wherein the control system is operable tomove the tilted kettle back toward an upright position and then tosubsequently tilt the kettle to dump the popcorn again.
 23. Apparatus asin claim 21 wherein said indicator provides an audible indication to theoperator.
 24. Apparatus as in claim 21 wherein said indicator provides avisual indication to the operator.
 25. Apparatus as in claim 15 furthercomprising an oil pump system for pumping cooking oil to the kettle atthe initiation of a cooking cycle, the controller system furtherresponsive to the sensed kettle temperature signal and operably coupledto disable the oil pump system in response to the kettle temperature.26. Apparatus as in claim 25 further comprising a kettle position sensorto sense when the kettle is in an upright position, the control systemcoupled to the position sensor and operable for disabling the oil pumpsystem when the kettle is not in an upright position.
 27. Apparatus asin claim 25 wherein the control system is operable to enable the oilpump system when the kettle temperature has exceeded the dumptemperature.
 28. Apparatus for popping popcorn comprising: a tiltablekettle including a heater to heat the kettle for popping uncookedpopcorn placed therein, the heater maintaining the kettle at anequilibrium start temperature when no popcorn is being popped; a sensoroperably coupled to sense the temperature of the heated kettle and tosense a fall in kettle temperature from said start temperature whichoccurs when uncooked popcorn is placed in the kettle; a control systemoperable for receiving said sensed kettle temperature from the sensorand responsive to the kettle temperature for initiating a cooking cyclewhen the kettle temperature falls below a predetermined temperature; thecontrol system further responsive to the kettle temperature whilepopcorn is being popped during the cooking cycle and the sensor sensingthe rise in kettle temperature which occurs as the popcorn is popped,the control system operable to end the cooking cycle and automaticallyproduce tilting of the kettle and dumping of the popped popcorn when thekettle temperature subsequently rises above said predeterminedtemperature.
 29. Apparatus as in claim 28 wherein the control system isfurther operable to cause a humanly perceptible indication to begenerated by an indicator when the kettle temperature rises back to astart temperature above said predetermined temperature after the popcornhas been dumped such that an operator is alerted to add another batch ofuncooked popcorn to the kettle and initiate another cooking cycle. 30.Apparatus as in claim 28 wherein the control system is further operablefor heating the kettle back up to the start temperature after thedumping of the popcorn so that the kettle is ready to receive and cookanother batch of popcorn.
 31. Apparatus for popping popcorn comprising:a kettle including a heater to heat the kettle for popping uncookedpopcorn placed therein; a sensor operably coupled to sense thetemperature of the heated kettle and generate a temperature signalindicative of the kettle temperature; an oil pump system for pumpingcooking oil to the kettle for popping the popcorn; a control systemresponse to said temperature signal and operably coupled to the oil pumpsystem for enabling and disabling the oil pump system in response to thekettle temperature.
 32. Apparatus as in claim 31 wherein the controlsystem is operable for disabling the oil pump system when the kettletemperature falls to a level below a predetermined minimum temperature.33. Apparatus as in claim 31 wherein the heater is switchable between anON position and an OFF position, the control system being operable fordisabling the oil pump system when said heater is switched to an OFFposition.
 34. Apparatus as in claim 31 wherein the kettle is tiltablebetween an upright position for popping popcorn and a dump position fordumping the popped popcorn, the apparatus further comprising a positionindicator for determining the position of the tiltable kettle, thecontrol system operable for disabling the oil pump system when theposition indicator indicates that the kettle is not in an uprightposition.
 35. Apparatus as in claim 31 wherein the heater is operable toheat the kettle to a start temperature for popping the popcorn, thecontrol system operable for enabling the oil pump system toautomatically pump oil to the kettle when the kettle temperature isproximate said start temperature.
 36. Apparatus as in claim 31 whereinthe control system is further operable for automatically pumping oil tothe kettle in response to the sensed kettle temperature.
 37. Apparatusas in claim 31 wherein the control system is further operable forinitiating a cooking cycle when the kettle temperature drops below apredetermined minimum point after uncooked popcorn is placed therein,the control system enabling the oil pump system for pumping oil to thekettle for the cooking cycle and subsequently disabling the oil pumpsystem until a subsequent cooking cycle begins whereby to generallyprevent excess oil in the kettle in a single cooking cycle.
 38. A methodfor popping popcorn comprising: placing uncooked popcorn in a kettle;heating the kettle for cooking and popping the uncooked popcorn placedtherein and dumping the kettle for dispensing the popped popcorn;monitoring a kettle temperature condition and selectively heating anddumping the kettle in response to said monitored kettle temperaturecondition.
 39. The method of claim 38 further comprising providing ahumanly perceptible indication when the kettle is heated to apredetermined start temperature to alert an operator to load the kettlewith unpopped popcorn.
 40. The method of claim 38 wherein the kettle istiltable and further comprising tilting the kettle in response to saidtemperature condition to dump the popcorn from the kettle after it hasbeen popped.
 41. The method of claim 40 further comprising sensing atemperature drop in the kettle indicating loading of the kettle withuncooked popcorn after the kettle is heated and sensing a subsequenttemperature rise in the kettle indicating that the popcorn is beingpopped; tilting the kettle and dumping the popcorn when the kettletemperature subsequently rises and exceeds a predetermined dumptemperature indicating that a portion of the popcorn is popped.
 42. Themethod of claim 41 further comprising initiating a cooking cycle whenthe kettle temperature drops when the uncooked popcorn is added anddecreases below a predetermined cycle temperature.
 43. The method ofclaim 42 wherein said cycle temperature is approximately equal to saiddump temperature.
 44. The method of claim 38 further comprisingdelivering an amount of cooking oil to the kettle in response to saidmonitored kettle temperature condition.
 45. The method of claim 44further comprising preventing the delivery of any additional oil to thekettle after said amount is delivered until after the kettle is dumped.46. The method of claim 38 further comprising pumping oil to the kettlewith an oil pump system and disabling the oil pump system in response tosaid monitored kettle temperature condition.
 47. The method of claim 38wherein the kettle is movable between an upright position for cookingthe popcorn and a dump position for dumping the popped popcorn, themethod further comprising pumping oil to the kettle with an oil pumpsystem and disabling the oil pump system when the kettle is not in anupright position.
 48. The method of claim 44 further comprisingautomatically pumping oil to the kettle from an oil pump system inresponse to said monitored kettle temperature condition.
 49. A methodfor popping popcorn comprising: heating a kettle for cooking and poppinguncooked popcorn placed therein; monitoring the temperature of theheated kettle; providing a humanly perceptible indication when thekettle has been heated up to a predetermined start temperature to alertan operator to load the kettle with uncooked popcorn.
 50. The method ofclaim 49 wherein said predetermined start cook temperature is in therange of approximately 500° F. to 550° F.
 51. The method of claim 49further comprising sensing a drop in kettle temperature indicatingloading of the kettle with uncooked popcorn to be cooked and popped;and, initiating a cooking cycle when the monitored kettle temperaturedecreases below a predetermined cycle temperature.
 52. The method ofclaim 51 wherein said predetermined cycle temperature is in the range ofapproximately 425° F. to 500° F.
 53. The method of claim 49 furthercomprising providing an audible indication in response to said kettlebeing heated.
 54. The method of claim 49 further comprising providing avisual indication in response to said kettle being heated.
 55. Themethod of claim 49 further comprising: sensing a drop in kettletemperature indicating loading of the kettle with uncooked popcorn to becooked and popped and sensing a subsequent rise in the kettletemperature indicating that the popcorn is being popped; tilting thekettle and dumping the popcorn when a portion of the popcorn has beenpopped and the kettle temperature subsequently rises and exceeds apredetermined dump temperature.
 56. The method of claim 55 wherein saidpredetermined dump temperature is in the range of approximately 425° F.to 500° F.